Status and Availability

2012 Feb 25NIRI is available for queue and classical imaging observations.

Not all filters are available at any one time; check the filter list to see which are currently installed.

NIRI occasionally suffers from vertical striping and shifts in DC levels which can both vary from quadrant to quadrant. Details can be found here.

Previous News Items

2010 Jun 21The NIRI
focal plane unit which holds the various spectroscopic slits and imaging masks stopped responding on the night of June 19. On Sunday we were able to nudge the wheel to the f/6 imaging position and today engineers locked out the mechanism so that NIRI may be safely used for imaging with any camera in combination with the f/6 beam splitter and f/6 focal plane mask. Spectroscopy will be unavailable until NIRI can be warmed up and taken into the lab for repairs. Until we can disassemble NIRI to assess the severity of the problem it is unknown how much time will be required to return NIRI to a fully operational state.

2010 Apr 29The beam splitter wheel, which determines the size of the beam to direct to the science detector, is again having problems moving into position reliably. In order to resume science operations with NIRI, we have decided to fix the beam splitter at the f/6 position which sends the largest field of view through the instrument and can therefore be used with all three cameras. This results in a several percent increase in background (which is not uniform over the field) and slightly different vignetting when used with Altair and its field lens. See here for more details.

2010 Apr 15NIRI is cold and the beam splitter mechanism is working perfectly! NIRI is about to be re-installed on the telescope and should be available for science tomorrow.

2010 Apr 2The beam splitter wheel detent roller and bushing were removed and refurbished (the inner bushing had translated axially and was binding the roller against the detent arm) and the Phytron drive motor was replaced. While NIRI was open we recut the f/32 4-pixel slit to be parallel and vertical.

2010 Mar 24
NIRI is cold again, and there are now no slipping gears, however, there is still too much friction in the system for the motor to move the beam splitter wheel reliably while cold. The two likely culprits which could be causing this problem are the Geneva detent mechanism roller and/or the drive motor. We have therefore begun another warm up in order to work on these components. If all goes well NIRI should be available for science in ~3 weeks. More information will be posted here as it becomes available.

2010 Mar 15
The beam splitter wheel gear box was removed and disassembled. An inspection uncovered two places where the gears had spun on their shafts, so new set-screws were installed, including one which was bent and rubbing against a nearby gear. The Geneva gear and roller assembly was re-lubricated and the gear box was re-installed. We are
continuing with a thorough examination of other mechanisms while NIRI is in the lab, and will start cooling the dewar on Thursday March 18, with an on-sky target date of March 24.

2010 Mar 4
The NIRI beam-splitter wheel which is used to select between the three cameras
(optomechanical layout)
stopped responding on the afternoon of March 2. Troubleshooting indicates that the problem is internal and mechanical.
We will therefore begin warming NIRI today to investigate further and expect NIRI to be unavailable for science through the end of March.

2009 Sep 10
After a very thorough investigation, Gemini engineers discovered two problems with NIRI:
the detector controller electronics had an intermittent issue with the slow clocks,
and there was a short circuit between two pins in the detector mount.
These problems were fixed and routine maintenance was performed on the detector mount and cabling.
Testing is ongoing, and NIRI is now being scheduled for science operations.

2009 Aug 27
Work on the NIRI detector and electronics is ongoing,
and we are planning on cooling down next week to do more testing.
The earliest NIRI may return to science operations is September 10.

2009 Aug 12
Over the past four months we have seen several failures of the NIRI
detector to activate. These events lasted anywhere from several minutes
to several hours, and the instrument was unusable during these periods.
We contacted outside experts and were investigating options for
troubleshooting the problem.

Unfortunately, on the night of 2009 Aug 9 this condition transitioned
from intermittent to persistent, and we have not been able to activate
the array since.

As the cause and severity of the problem are still unknown, it is
impossible to provide an exact date when NIRI will be fixed. We are
starting to warm up NIRI today so that we may perform diagnostics on
the detector and control electronics. We are hoping that the problem
can be located and resolved quickly so that NIRI can return to science
operations by the end of August. However, NIRI may be unavailable for
longer if invasive work is required.

2004 Nov 5
The Oct 21 - Nov 4 run was nearly wiped out by bad weather, with clouds
and high humidity during the entire run. The problems with the array
readout culminated during this run, and on Oct 25 we changed out the
coadder board, and on Nov 1 we disabled the window cover ionizer. Ever
since the array has been behaving very well, and we have seen very few
instances of the quadrant bias variations or pattern noise.

2004 May 16
Third and fourth NIRI runs completed. Weather generally better during
both runs, but with only a few nights of excellent seeing. ALTAIR now in
frequent use with NIRI, with almost all Band 1-3 programs under way or
completed. Problems with electronic pickup on array frames were
somewhat alleviated starting on April 5. Typically 90% of the data
frames obtained in each program since then are uncontaminated; we
continue to work toward a complete solution to this problem. One of
NIRI's internal motors began failing toward the end of the May run,
limiting our observing options during the final three nights of the May
run. That motor is being replaced during mid-May and it is expected
that the instrument will be available for use at the start of the May 29
- June 9 run.

2004 Mar 12
Second 2004A observing run completed - weather conditions were
appallingly bad - heavy snow/thunderstorm complete with electrical
damage closed telescope for several nights; weather poor thereafter
(clouds, horrible seeing) - only able to do parts of the few programs
that could tolerate those conditions. Continued problems with vertical
striping and different dc levels in the four array quadrants in some
images; as the pattern appears nearly constant, some workarounds for
this are possible.

2004 Feb 12
First 2004A observing run completed - weather conditions were generally
poor (esp seeing). Some problems with array dc level instability
visible as vertical striping and as different dc levels in the four
array quadrants in some images; otherwise instrument performance was
nominal.

2004 Jan 20NIRI update,
Dewar being cooled after mechanical overhaul and replacement of some
filters in preparation for 2004B